Modern wireless communication devices often support both wireless local area network (WLAN) connections and cellular connections. In some scenarios, data can be exchanged between a WLAN chip and a cellular chip. For example, in the case of device tethering, a wireless communication device can serve as a WLAN access point and enable one or more further devices, referred to as tethered devices, share a cellular network connection with the wireless communication device.
In most present device architectures, the WLAN chip and the cellular chip are each connected to an application processor. As such, in a tethering scenario, data arriving from the cellular network has to be passed from the cellular chip to the application processor, and then from the application processor to the WLAN chip, which can forward the data to the tethered device. Bridging the WLAN chip and the cellular chip via the application processor in this manner can result in the application processor drawing power to stay in an active state to support the bridging even if the application processor is not performing any further function.
Some attempts have been made to reduce the power drawn to support conveying data in support of tethering through the use of integrated WLAN and cellular chips, which provide both WLAN and cellular connectivity on a single chip. Such integrated WLAN and cellular chips can autonomously handle tethering-related communication between the WLAN and cellular stacks without involving the application processor, and thus can reduce power consumption by enabling the application processor to sleep during tethering. However, usage of an integrated WLAN and cellular chip can be undesirable, as it can limit flexibility in device design.
In another alternative architecture that can be used to reduce the power drawn to support tethering, a direct link can be implemented between the WLAN chip and the cellular chip to enable forwarding of data between the two chips without involving the application processor. However, this architecture requires the implementation of an additional high speed interface on both the WLAN chip and the cellular chip to support the direct link, which can result in increased cost, and which can undesirably increase the chipset footprint in size-limited mobile devices.